Decimal read-out for fluidic counters



.Filed April 11, 1968 June 17, 1969 RENDER ET AL 3,450,341

DECIMAL READ-OUT FOR FLUIDIG COUNTERS Sheet of 4 l'l' vl'lvkg 3 5 READ 007' MMWW/ .BY mm 10% Ariel/MW June 17, 1969 A. B. RENDER L 3,450,341

DECIMAL READOUT FOR FLUIDIC COUNTERS Sheet Filed April 11, 1968 W a/wd/ M .BY [5mm M /(Mm az/ uwu A. B. RENDER ET AL 3,450,341

DECIMAL READ-OUT FOR FLUI IIDIC COUNTERS June 17, 1969 Sheet 3 of4 Filed April 11, 1968 June 17, 1969 A.B.RENDER ETAL 3,450,341

DECIMAL READ-OUT FOR FLUIDIC COUNTERS Filed April 11. 1968 Sheet 4 of 4 United States Patent US. Cl. 235-201 16 Claims ABSTRACT OF THE DISCLOSURE A decimal read-out for fluidic counters comprises a block in which there is located a plurality of cavities, each connected to different outputs of a fluidic counter, and each housing a movable piston which moves in re sponse to a corresponding output from the fluidic counter. A flexible tape passes through the cavities, the tape having one fixed end, its other end being attached to a return spring. When any piston is raised by an output from the fluidic counter, the piston abuts the tape which is then displaced by a predetermined amount. Printed symbols on the tape indicating displacements thereof, are thus moved to a position, whereby an image of a particular symbol is focussed by optical means on a display screen. The apparatus serves as a binary to decimal converter.

Background of invention This invention relates to apparatus for converting signals from a fluidic counter from one system to another system, for example, to provide a decimal read-out from binary coded decimal fluidic counters.

It is common practice, in most forms of counter circuit to use the binary representation of numbers. In fluidic systems, in particular, the binary system is universally employed. When it is necessary to present numerical information to an operator, the binary system is inconvenient since a read-out in binary form will require subsequent conversion to decimal for-m. Frequently, to simplify this conversion, counting is carried out in the binary coded decimal form in which numbers remain in decimals with the individual digit of each decade expressed as a binary number. Binary to decimal conversion is still required before the number can be presented as a decimal read-out.

Summary of the invention Thus, an object of the present invention is to provide a binary to decimal converter for connection to the output of a fluidic counter.

It is a further object of the invention to present the result of conversion as a read-out in a manner suitable for an industrial instrument.

It is another object of the invention to provide a binary to decimal converter capable of accepting continuous inputs from the output of a fluidic counter, without the need for the counter input to return to zero between readings.

According to this invention, apparatus for converting fluidic output signals corresponding with numerical values to the base of a first radix, to mechanical displacements corresponding with numerical values to the base of a second radix, comprises a plurality of elements each movable respectively in response to a corresponding output signal from a fluidic counter, said elements bearing against a common displaceable member and each being movable by a predetermined extent whereby said member will be displaced by an amount corresponding to the numerical sum to the base of the second radix, of the fluidic counter output signals.

According to a preferred form of the invention and particularly applicable to a numerical system, the apparatus comprises a block containing a plurality of cavities for individual connection to corresponding output connec tions of the fluidic counter, each cavity containing an element capable of movement in response to the corresponding output signal from the fluidic counter to bear against a common flexible strip, whereby the flexible strip will be displaced by an amount corresponding to the said sum of the fluidic counter output signals.

In the above arrangement, preferably one end of the strip is fixed while the other end is attached to an elastic member capable of supplying the energy to return the strip to a position corresponding to zero output signal from the fluidic counter.

It is an advantage to include visual display means, operable in connection with the flexible strip, to display values, to the base of the second radix, equivalent to the sum of the fluidic counter output signals. Preferably the flexible strip is transparent and carries printed symbols arranged at regular intervals along its length. When the strip is displaced by an output from the fluidic counter, the symbol corresponding to the said output is brought to a position in which it can be made visible on a screen by an optical system.

Description of drawings Other objects and advantages of the invention will become apparent from the following description of exemplary embodiments referring to the accompanying schematic drawings in which:

FIGURE 1 shows the converter in side section.

FIGURE 2 shows in section and on an enlarged scale a modified construction of cavity which may be used.

FIGURE 3 shows a modified form of movable element.

FIGURE 4 illustrates means to provide for repetitive sampling of each output of the fluidic counter.

FIGURE 5 illustrates in perspective an example of a complete converter.

FIGURE 6 shows an embodiment of the converter having adjusting screws for limiting the travel of the movable elements.

FIGURES 7 and 8, illustrate amplification means for fluidic counter inputs.

FIGURE 9 is a further schematic view of the amplification means.

FIGURES 10, 10a, 11 and llb show further modified forms of movable elements.

FIGURE 12 is a block diagram of a converter system.

FIGURE 13 shows a return spring arrangement.

Description of examples of the invention FIGURE 1 illustrates a basic principle of the device in which a block 1, made in two parts, is provided with four cavities 2. These cavities each contain a piston 3, the top ends of which are shaped to conform with the curved top of the cavities. Each piston is lifted into the top of its cavity by means of that pressurized air output of the fluidic counter which is introduced into the area below the piston through one of the inlets 4, the l, 2, 4 and 8 fluidic counter outputs each being connected to the appropriate inlet.

A flexible transparent strip 5 is clamped between the two parts of block 1 at the left hand end, and passes along a small gap between the two parts, and is held in tension by a light spring 6. Digits from 0 to 9 are printed on the strip at regular intervals over the area marked 7. A light source and a lens system magnifies and projects these numbers onto a translucent screen 8. With all the pistons in the off position, the printed on the tape is in line with the optical system and is projected on the screen. The length of the top curved ends of the cavities are such that the linear displacements of the tape are 1, 2, 4 and 8 units. A 1 fluidic counter output raises the piston in the cavity of the lower block, and carries the tape into the corresponding cavity of the upper block. The spring loaded end of the tape is pulled towards the left, and brings the digit 1 on the strip, into line with the optical system. Similarly, a 2 fluidic counter output raises the piston in the appropriate cavity displacing the tape such that the digit 2 is drawn into line with the optical system and is projected on the screen. Fluidic counter outputs 1 and 2 (corresponding to decimal 3) simultaneously applied to the converter brings digit 3 into position to be projected, and each of the other digits, from 0 to 9, is brought to the correct position by the appropriate binary coded inputs. The manner of presentation of the read-out is similar to the type commonly used in electronic instruments. It has the advantage that all the digits are displayed in one plane, and that the instrument is self illuminated. The units can be produced in compact form suitable for side by side assembly, so that any number of decades can be presented in a single read-out unit.

FIGURE 6 shows a modified form of the converter, in

16, in the top of the block 1. The screws 15 are arranged to project slightly from the domes of the cavities 2, so as to limit the extent of travel of the movable elements 3 when raised. These adjusting screws 15, obviate the necessity for the precise manufacture of the cavities 2 in the block 1.

If numerals with reasonable physical dimensions are used the necessary pitch between adjacent digits indicates that the movement of the strip in response to an input of a high value is correspondingly large. The largest piston, for example the 8 digit, thus becomes too bulky for use in a compact mechanism. This difiiculty can be overcome by taking advantage of the fact that, in the binary coded decimal system, the 4 and 8 inputs are never required together. Thus, it is possible to use two pistons of the same size, pressurising only one for a 4 digit and pressurising both when the "8 input is present.

An exemplary arrangement is shown in FIGURE 2, which illustrates part of a block containing two identical cavities. A fluid passage 9, connects the upper part of the 8 chamber with the lower part of the 4 chamber. A non-return valve 10, is incorporated in the inlet to the 4 chamber to prevent flow in the reverse direction. An input to the "4 inlet unseats the non-return valve and raises the piston. The passage 9 is sealed by the 8 piston and thus only the one piston is pressurised. An input at the 8 inlet raises the piston and uncovers the passage 9, to allow fluid to flow into the 4 chamber. The non-return valve is seated and the 4 piston is also raised. Thus, both pistons are raised by an 8 input.

In the form described above the read-out is only suitable for single readings, after each of which the pistons are returned to positions corresponding to zero input to the converter. This is adequate for many purposes but, if a continuous read-out of a frequently changed state is required, some modification is necessary to overcome the friction loading on the flexible strip. One arrangement is shown by FIGURE 3 which illustrates part of a lower block. A piston 11 takes the form of a cylinder mounted with its longitudinal axis at right angles to its path of movement. The upper part of the block is replaced by a roller 12 fixed at each side of the cavity in the lower block. This arrangement leaves the flexible strip free to slide when displaced. When, for example, the converter has responded to a 4 fluidic input and the corresponding piston is in a raised position, a subsequent fluidic input equivalent to will additionally cause the piston to rise that corresponds to a fluidic input of 1. The tape will then slide through the roller which small adjusting screws 15 are located in tappings arrangement and allow the reading to change to 5. With the previous arrangement, the friction at the 4 piston would have prevented the second piston from rising. It can be expected that the system employing rollers will require rather higher operating pressures to maintain contact between the two rollers and the piston, to prevent locking against the side of the cavity.

In order to simplify manufacture, an alternative construction of the pistons 11 for a continuous read-out system is shown in FIGURES 10, 10a, 11 and 11b. In FIGURES 10 and 10a a piston 11 of rectangular form has a recessed portion in its upper surface to accommodate a roller 18. The roller 18 is located in the recess of the piston 11, and freely rotates about a pin 17, which passes through the sides of the piston 11 and the axis of the roller 18.

FIGURES 11 and 11a illustrate another modified piston 11, of a rectangular form having a semicylindrical shaped end 19. The end 19 contains a recessed channel 20, substantially following the curve of the semicylindrical end 19. The width of the channel 20 is arranged to be slightly greater than that of the tape 5, so that the tape 5 is carried within the channel when the piston 11 is raised. The depth of the channel 20 is such that the tape 5 is free to slide within it, when the piston 11 is at its topmost position within its respective cavity 2.

In a single read-out arrangement, means is provided for repetitively sampling each output of the fluidic counter, allowing the sample to actuate the read-out device and return the visual display to zero before the next sample is handled.

Such an arrangement is illustrated in FIGURE 4, where a sampling valve 13, which could be either rotary or reciprocating in action, is independently operated by the fluidic input. The essential feature of this arrangement is that the porting should be so arranged that bistable elements 14 should be alternatively set to give a repeat of the counter reading at the time of sampling, and then reset to zero on all four elements. However, the above sampling arrangement may be dispensed with when the pistons 11 described with reference to FIGURES 3, 10, 10a, 11 and 11a are used.

It is possible to operate the pistons '11 by connection between the inlets 4 and the fluidic counter outputs, provided that suitable nozzles are used in the fluidic counter outputs, for example, nozzles having the dimensions 0.015 x 0.040". However, if the dimensions of the nozzles are reduced, it becomes necessary to use some form of amplification for the fluidic inputs to the converter. One suitable form of amplification means, comprises bistable ball valves 10 located within suitable chambers, as is shown in FIGURES 7, 8 and 9.

In FIGURE 7, a block 21 contains ball valves 23 lo cated in chambers 25. The block 21 is attached to the lower portion of the block 1. Drillings 26 in block 21 are arranged to correspond with the positions of the inlets 4 in block 1. In the particular arrangement shown in FIGURE 7, which is a modified form of the 4 or 8 read-out embodiment described with reference to FIG- URE 2, one of the inlets 4 leads to a chamber 27 that houses a ball valve 24.

FIGURE 8 illustrates a sectioned side elevation of the converter, in which the inlet and outlet connections of the block 21 can be seen. FIGURE 9 shows these inlet and outlet connections in greater detail.

In FIGURE 9, a main air supply enters an inlet 28 that is connected to a restriction 29, having an exit port 30 to the chamber 25. When no fluidic counter output is present at an inlet 35, the main air supply causes the ball valve 23 to be moved away from the exit 30, as is shown in the drawing. A vent 33 allows air from the main supply to escape to atmosphere, so that the pressure on the left hand side of the ball 23 is only slightly above atmospheric. The exit 30 is of a slightly wider cross-section than the cross-section of the restriction 29 so as to produce a jet pump effect which causes the inlet of a restriction 31, connected to the underside of the piston 3 (not shown) in the chamber 2 (not shown), to be held at sub-atmospheric pressure. The restriction 31 is connected to the exit port 30, and to a wider cross-section outlet chamber 32, which leads to the underside of the ball 24, as shown in FIG- URE 8. The restriction 31 is arranged at a right angle to the axis of the exit port 30.

A fluidic counter output is applied to the inlet 35, which in turn is connected to a drilling 34 of smaller crosssection. The pressure of the fluidic counter output is greater than that in the chamber 25, and thus the ball 23' is driven towards the exit port 30. The pressure of the fluidic counter output is such that the ball 23 is held against, and therefore, seals off the main air supply issuing from the exit port 30. Thus the main air supply enters the restriction 31, and the outlet chamber 32, to cause the ball 24 to rise in the chamber 27, as shown in FIGURE 8. The ball 24 is arranged to be smaller than the crosssection of the chamber 27, and hence the main air supply passes around the ball 24 to the underside of the piston 3, the piston 3 then rises due to the pressure exerted by the main air supply.

Although the pressure within the chamber 27, and 32 and the restriction 31, will eventually rise to that of the main air supply, once the piston 3 has been raised, the ball 23 continues to be held against the exit port 30. The force exerted by the fluidic counter output acts over half the surface area of the ball 23, whereas the force exerted by the main air supply through the exit port acts on a much smaller area of the ball 23.

When the ball valve amplifying means described above, is used, the sampling arrangement described with reference to FIGURE 4- can be dispensed with. All that is required is the continuous on/oif cycling of the main air supply to the ball 23. A suitable arrangement is shown in FIGURE 12. A rotary or reciprocating valve 36, continuously switches the main air supply on and off to the line 37, which in turn is connected to the chamber 28 (not shown) of the converter 38. The inlets 4, are supplied from the fluidic counter output as previously described.

FIGURE 13 illustrates an alternative return spring arrangement for the tape 5. The spring 6 of FIGURE 5, is replaced by a torsion spring (not shown) fixed to the outer shell of a drum 39, and a fixed spindle 40, which passes through the axis of the drum. The drum 39 rotates about the spindle 40 when the tape is moved horizontally by the action of the pistons 3. The drum 40 rotates against the action of the torsion spring. Adjustment of the initial spring load is provided by a rotatable disc 41, attached to the spindle 40. After adjusting the initial spring load the disc 41 is locked in position by means of a screw 42, which passes through a slot in a side wall of the converter casing.

What we claim is:

1. Apparatus for converting fluidic output signals corresponding with numerical values based on a first radix, to mechanical displacements corresponding with numerical values based on a second radix, comprising a block defining a plurality of cavities therein, connecting means for connecting each of said cavities to corresponding outputs of a fluidic counter so as to supply said fluidic signals thereto, inlet means associated with each of said'cavities and said connecting means, piston means housed within each cavity and capable of reciprocal movement therein in response to said fluidic signals, and flexible strip means passing through each of said cavities and over each of said piston means, said strip means being displaceable by said piston means such that one end of said strip means is displaced by a predetermined amount when said piston means have moved in response to a particular one of said fluidic signals, said amount being proportional to said numerical values based on said second radix.

2. Apparatus according to claim 1, wherein said flexible means is a flexible strip, said piston means are pistons located above said inlet means, said cavities are vertical tubes in which said pistons reciprocate, part of said strip passing through the side walls of each tube, and over the upper surface of each piston, a space normally being defined in each tube by a portion of said strip within said tube and the roof of said tube, the shape of said roof substantially conforming to the upper surface of said piston, and in operation, when any of said pistons are raised by one of said fluidic signals, said piston abuts said portion of said strip, whereby said strip is carried up inside said space towards said roof, thereby causing said one end of said strip to be displaced.

3. Apparatus according to claim 2, additionally comprising spring means for attachment to one end of said strip, the other end of said strip being fixed relative to said spring means, said spring means normally biasing said strip to conform to a single plane when said fluidic signals are zero and in operation, when any one of said pistons are raised in response to one of said fluidic signals, said spring means provide resilient forces for returning said strip to said single plane when said pistons are lowered.

4. Apparatus according to claim 3, wherein each of said pistons have a hemicylindrical upper surface for abutting said portion of said strip.

5. Apparatus according to claim 4, additionally comprising visual display means operable in association with said strip for displaying values equivalent to the sum of said fluidic counter output signals applied to said inlet means.

6. Apparatus according to claim 5 wherein said strip is transparent, having numbers inscribed thereon at regular intervals along part of its length, and said visual display means comprise optical means associated with said transparent strip, such that when said strip is displaced by a particular fluidic signal, the number inscribed on said transparent strip corresponding with said fluidic signal is brought to a position whereby it is focussed by said optical means on said display means.

7. Apparatus for converting fluidic output signals corresponding with numerical values based on a first radix, to mechanical displacements corresponding with numerical values based on a second radix, comprising a block defining a plurality of vertical tubes therein, connecting means for connecting each of said tubes to corresponding outputs of a fluidic counter so as to supply said fluidic signals thereto, inlet means associated with each of said tubes and said connecting means, a piston housed within each of said tubes for reciprocal movement therein in response to said fluidic signals, a flexible transparent strip, part of which passes through the side walls of each tube, and over the upper surface of each piston, a space normally being defined in each tube by a portion of said strip within said tube and the roof of said tube, the shape of said roof substantially conforming to the upper surface of said piston, and in operation, when any of said pistons are raised by one of said fluidic signals, said piston abuts said portion of said strip, whereby said strip is carried up inside said space towards said roof, thereby causing said one end of said strip to be displaced, another part of said strip having numbers inscribed thereon at regular intervals along its length, spring means for attachment to one end of said strip, the other end of said strip being fixed relative to said spring means, said spring means normally biasing said strip to conform to a single plane when said fluidic signals are zero, and in operation, when any one of said pistons are raised in response to one of said fluidic signals, said spring means provide resilient forces for returning said strip to said single plane when said pistons are lowered, visual display means operable in association with strip for displaying values equivalent to the sum of said fluidic counter output signals applied to said inlet means, and optical means co-operating with said display means, such that when said strip is displaced by a particular fluidic signal, the number inscribed thereon corresponding with said fluidic signal is brought to a position whereby it is focussed by said optical means on said display means.

8. Apparatus according to claim 7 wherein each of said pistons has a hemicylindrical upper surface for abutting said part of said strip.

9. Apparatus according to claim 8 wherein said upper surface permits said strip to slide freely thereover when any one of said pistons is displaced by one of said fluidic signals, when at least one other of said pistons has already been displaced, thereby enabling continuous, different fluidic signals to be continuously supplied to said inlet means.

10. Apparatus according to claim 9 wherein each piston is cylindrical and is arranged in its respective tube with its longitudinal axis parallel to the width of said strip, a roller being additionally provided at either side of the upper side walls of each tube, the strip passing beneath each of said rollers and over the top of each piston.

11. Apparatus according to claim 10 wherein said cylindrical piston is a roller pivotally mounted at the top of a base portion.

12. Apparatus according to claim 7 wherein each of said pistons has a hemicylindrical upper surface for abutting said part of said strip, said upper surface having a recessed channel the width thereof being slightly larger than the width of said strip so as to allow said strip to slide freely within said channel when said piston is displaced by one of said fluidic signals.

13. Apparatus according to claim 7 additionally com prising tappings within said block, each tapping being provided with an adjustable screw dependinginto each tube above its respective piston, so that when said piston is displaced by said fluidic signal, an upper side of said piston remote from said strip carried on the upper surface thereof, abuts said depending end of said screw so as to prevent contact between said strip and the roof of said tube.

14. Apparatus according to claim 7 wherein a ball valve is connected to said inlet means of each tube.

15. Apparatus according to claim 7 when connected to a sampling device for supplying said fluidic output signals from the fluidic counter for displacing particular ones of said pistons, and for allowing said pistons to return to their starting positions before the following fluidic sample is supplied.

16. Apparatus according to claim 7 wherein fluidic amplification means are connected to each said inlet means for amplifying the fluidic output signals supplied thereto, When said inlet means include a nozzle having a crosssection which would normally limit the efiective fluid pressure exerted on said pistons.

References Cited UNITED STATES PATENTS 3,101,233 8/1963 McNaney 235201 3,263,922 8/1966 Voit 235-201 3,319,885 5/1967 Eige 235----201 RICHARD B. WILKINSON, Primary Examiner.

LAWRENCE R. FRANKLIN, Assistant Examiner. 

